CVE-2019-1849: Cisco IOS XR Software BGP MPLS-Based EVPN Denial of Service Vulnerability

Severity: medium (CVSS 6.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2019-05-16 · updated 2026-06-17
Weakness: CWE-754

Description

A vulnerability in the Border Gateway Patrol (BGP) Multiprotocol Label Switching (MPLS)-based Ethernet VPN (EVPN) implementation of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to trigger a denial of service (DoS) condition on an affected device. The vulnerability is due to a logic error that occurs when the affected software processes specific EVPN routing information. An attacker could exploit this vulnerability by injecting malicious traffic patterns into the targeted EVPN network. A successful exploit could result in a crash of the l2vpn_mgr process on Provider Edge (PE) device members of the same EVPN instance (EVI). On each of the affected devices, a crash could lead to system instability and the inability to process or forward traffic through the device, resulting in a DoS condition that would require manual intervention to restore normal operating conditions.

Affected products

Cisco IOS XR Software: from 6.1.0 before 6.3.3; from 6.4.0 before 6.4.2; from 6.5.0 before 6.5.2; from 6.6.0 before 6.6.1 — fixed in 6.3.3, 6.4.2, 6.5.2, 6.6.1

How to fix

Upgrade to a fixed version: Cisco IOS XR Software 6.3.3, 6.4.2, 6.5.2, 6.6.1. Check the vendor advisory for mitigations.

References

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